1. Field of the Invention
The present invention relates to a liquid-cooled heat sink for an electronic device, more particularly to a liquid-cooled heat sink, in which the installation position of a pump unit and the flow path of cooling liquid in the heat exchange module are altered, thereby minimizing the size, simplifying the structure and enhancing heat dissipating effects of the liquid-cooled heat sink.
2. The Prior Techniques
When computer or any other electronic devices operate, the heat produced by the central processor unit (CPU), chips and other processing units in the chassis has to be expelled fast and effectively to exterior to keep the temperature in chassis within the manufactory suggested range, and therefore to protect the electronic units from being damaged or destroyed.
Air-cooled heat sinks are generally and traditionally used to cool down the CPU, the chips or other processing unit. In most cases, heat sinks are in contact with an outer surface of the CPU, the chip or the other processing unit in order to absorb heat while a fan unit is placed on or nearby the heat sink assembly to expel the generated heat on the fins by downstream air flow produced by the fan unit. Today, with frequent upgrades of the CPU and the chips, more calculations should take place in these units since more heat is created. Traditional air-cooled heat sinks can no longer meet the requirement of high-end computers or electronic devices.
Another cooling method is the liquid-cooled system. The liquid-cooled system utilizes a pump to circulate liquid within a looped system, while providing a heat exchanger to absorb the heat transferred by the liquid and to expel. Some liquid-cooled heat sinks are disclosed by US Patents, like U.S. Pat. Nos. 7,971,632, 8,245,764, 8,274,787 and 8,356,505.
In general, the liquid-cooled heat sink provides higher effective heat dissipation ability. However, the liquid-cooled heat system includes more components. This can potentially increase the assembly time and size of the cooling system, which can cause trouble on suit user's requirements. More components could also have increased leakage potential factor in the liquid-cooled heat sinks. Additionally, a large size of the system can affect the work effectiveness of the pump to be low, which causes the dissipating rate hard to improve.
FIG. 1 illustrates a heat exchange module H employed in a prior art heat sink. The heat exchange module H includes a fin assembly H1 constituted by a plurality of fins disposed in parallel manner, a plurality of connection passages H2 extending through two end portions of the fin assembly H1. The first end portion of the fin assembly H1 defines a first chamber H3 while the second end portion thereof defines two second chambers H41, H42. The second chamber H41 has a bottom surface formed with an inlet opening H5 for connection with a liquid inlet tube (not visible). The other second chamber H42 has a bottom surface formed with an outlet opening H6 for connection with a liquid outlet tube (not visible). Once the cool liquid, after absorbing the heat, enters into the second chamber H41 via the inlet opening H5, the cool liquid flows into the first chamber H3 via a portion of the connection passages H2 interconnecting the first chamber H3 and the second chamber H41. Afterward, the cool liquid flows from the first chamber H3 into the other second chamber H42 via the other portion of the connection passages H2 interconnecting the first chamber H3 and the second chamber H42, thereby establishing a generally U-shaped flow direction (shown in solid arrow in FIG. 1). Upon activation of a fan unit (not shown) the heat absorbed in the cool liquid is dissipated by the fin assembly H1 while the liquid flows through these chambers.